The present invention relates to techniques of carrying out correction of feature images which satisfy a predetermined condition. The present invention also includes techniques of detecting special images for the purpose of correction. In addition, the special images also include harmful images which may cause a harm to a human body. Therefore, the present invention relates to a method of detecting harmful images, a method of detecting differences in images, and an apparatus, and in particular relates to a method of detecting harmful images, a method of detecting differences in images, and an apparatus, wherein a difference in the scene configurations of two images is detected to detect the difference in the images. In addition, the harmful images include a flash, rapidly changing image sequences, a subliminal image, and the like.
In editing images, edition such as deleting and correcting of the feature images is needed. Particularly, with regards to harmful images, there is such a need to do this because of the following reasons. It has been generally found that images such as a flicker image contained in a video which repeats a flash within a short duration, and a subliminal image in which an image of such short duration that people cannot recognize is inserted, may cause a harm to a human body. There are inter-individual differences in the degree of influence on a human body from such images, and even if viewing the same image, there exist influenced people and uninfluenced people. Moreover, this influence is said to vary also depending on the environment for viewing images, and also relates to a positional relationship between a viewer and a video monitor, and to the brightness condition at a place for viewing.
If the above-described images come into a video such as in TV broadcast which a general public views, the area of influence is extremely huge, and the social liability at the video provider side may be accused. Therefore, video providers, such as a TV station, who provides video to a general public, checks and detects in advance whether such a harmful image has not come into before providing the video. Moreover, National Association of Commercial Broadcasters in Japan (NAB) whose members are broadcasting industry people has set a guideline on such harmful images.
Because an example of the harmful image is a change in a video within a short duration (from several frames to several seconds), it is difficult to visually check sufficiently, and in case of visual check a personal view of an examiner may enter. The influence of the harmful image also depends on the environment at the viewer side, so even if it is determined that a video does not have a problem under an environment of the examination, an influence may be caused depending on the actual condition of viewing.
For this reason, a conventional technique concerning a method of mechanically examining the harmful image is described in U.S. Pat. No. 6,937,764. In this conventional technique, a flash scene of video is detected and a feature quantity and a static image of the detected portion at the time of detection are presented as the detection results.
In the conventional technique described above, only mechanical detection of the harmful image can be carried out and there is no guideline how to correct the detected harmful image, and therefore how to carry out correction with respect to the detected harmful image is not known is a problem. For this reason, the examination result cannot be informed successfully to the video producer, so the corrected video by the video producer may be detected as a harmful image again. Especially, in case of TV broadcasting, the examiner of the harmful image belongs to a TV station and a corrector of the video belongs to the video production, in other words the examination and correction are often carried out by different organizations and different people, thereby causing the above-described problem.
In order to solve the above-described problem, it may be considered that as a guideline of correction of the harmful image, a correction method, with which correction was made due to a similar reason in the past and it was judged that the correction causes no problem, is utilized. In this case, people need to grasp the correction method of the image which was corrected in order to store the correction method of the image. However, even if only the corrected video is provided by the video corrector, and even if the correction method is provided from the corrector, there is no way to assure that the provided correction method is correct, thus causing a problem that the method of correcting image cannot be grasped correctly.